Attachment for motion-picture projecting machines



Aug. 17, 1948- J. D. EDMONDSON ATTACHMENT FOR MOTIONPICTURE PROJECTING MACHINES Filed Aug. 28, 1944 67 05 0 D. Z? 0 /20/7030, M WM;

Patented Aug. 17, 1948 ATTACHMENT FOR MOTION-PICTURE PROJECTING MACHINES Joseph D. Edmondson, Dayton, Tenn., assignor of one-fourth to J. F. Davis, one-fourth to Jess B. Goodrich, and one-fourth to John Ruifner,

all of Dayton, Tenn.

Application August 28, 1944, Serial No. 551,524

2 Claims.

The invention relates to an electrically operated fire protection attachment for a moving picture machine, and more especially to a safety device for use with motion picture projecting machines.

The primary object of the invention is the provision of a device of this character, wherein a shutter is automatically controlled for shutting 01f light through an orifice in the lamp house of motion picture projecting machines, to exclude the said light from the film of the latter, and thereby preventing the said film from catching on fire, should the latter break and interrupt its travel in the machine.

Another object of the invention is the provision of a device of this character, wherein sparking activity at the breaking point of the film will be eliminated, and thereby minimizing the possibilities of conflagration resulting from the inflammable character of the film catching fire from such sparking, the device being automatic in the working thereof, and is electrically controlled for instant operation on the breaking of the film when in motion within the projecting machine.

A further object of the invention is the provision of a device of this character, wherein the installment thereof on a motion picture projecting machine does not require any change or alteration in the latter, and is novel in the construction and arrangement of its parts, it being unique in the working thereof, eliminating fire hazards, and is positive in the operation of the same, with dispatch.

A still further object of the invention is the provision of a device of this character, which is simple in construction, thoroughly reliable and efiicient in operation, economical in the working of the same, readily and easily installed in a motion picture projecting machine, durable, requiring little or no attention, it being automatically controlled, and inexpensive to manufacture and install.

With these and other objects in view, the invention consists in the features of construction, combination and arrangement of parts as will be hereinafter more fully described in detail, illustrated in the accompanying drawing, which shows the preferred embodiment of the said invention, and pointed out in the claims hereunto appended.

In the accompanying drawing:

Figure 1 is a side elevation of dislocated portions of a motion picture projecting machine, showing the mechanically working parts of the device constructed in accordance with the invention in association therewith, the parts being in normal condition.

Figure 2 is a fragmentary plan view of the lamp house of the projector machine, showing the light shutter of the device in elevation and in open position, with operating adjuncts allocated therewith, the housing for the adjuncts being partly broken away.

Figure 3 is a detail elevation of one of the film controlled circuit closers of the device.

Figure 4 is a schematic View of the electric circuits of the device.

Similar reference characters indicate corresponding parts throughout the several views in the drawing.

Referring to the drawing, A designates generally the lamp house of a motion picture projector machine, which latter may be of any ordinary well known construction, and B denotes the film having a path of travel from a feeding magazine, not shown, to .a take-up reel, a portion thereof being identified at It], and such film has its path of travel between tracking and guide rollers ll and [2, respectively, in the usual well known manner past the exposure opening in the exhibitor parts I3 of the projector machine. The source of light for the film B is enclosed by the lamp house A, mounted rearwardly of the parts I3, and the light opening of such house is denoted at [4-, through which light is thrown to the exhibitor parts l3 for the projection of the pictures on the film B onto a screen.

The motion picture projector machine, including the feeding mechanism for the film B is as is customary, operated by an electric motor 15 arranged in an alternating current supply line, of volts capacity, having the circuit wires [6 and I1, respectively, and included in this line is an opening and closing switch l8, which is hand operated.

Upon the lamp house A, next to the opening I4, is attached a box-like enclosure body I8, which supports a vertically swingable shutter IQ, for closing the said opening 14, and the arm 20 of this shutter is connected by a pivot 2| exteriorly to such body ill for opening and closing movements. Within the enclosure body I8 is an electric solenoid 22 having its movable armature or core 23 through a pivotal link 24 connected with the arm 20 of the shutter I9, there being a clearance for the connection of the link and arm in the outer wall of the enclosure body [8, as best seen in Figure 2 of the drawing.

Arranged in the path of travel of the film B is 3 one or more circuit closers, the one or each including a pivoted spring actuated contact arm 25 adapted to be insulated by the said film B from a companion contact created by the guide roller I2 next thereto, grounded at 25. The film B normal-lyiholdssthe circuit closersopemtuntila breakage in the said film occurs, whereby thesaid closer at the point of breakage closes in the circuit 2! leading to the solenoid 22 which circuit- I has therein the switch arm 28 of a relay 29, while another switch arm 30 of suchrelay-completes::

a lock in such circuit to ground 3 I A transformer 32 for steppingdown the main. supply line voltage from 110) volts -to-1-6' volts is provided across the said supply:"line=,-wandt the primary of this transform-er being throughthe contact32and contact 33,respective1y,lwith which are i engageable switches 34 pivotally'1inke'd"at"35"to" the armature or core 23 of the solenoid to bet controlled thereby, the electrical connection 36 joining the switch arm-l Bil/for the contact 32- withthe transformer and solenoid; while (the switch 34 for'the contact '33 haS-itseIectrieconmotion 3''! r with I the line, the I contacts 32' I and 33 being common to theswitch I8- and-the flow of-thehcurrentof the main-linesupply is controlled accordingly to the positioning of such sWitch- IB'as tothecontacts=32 andNW- or the contact 38 in the main supply circuit;

The secondary of thetransformer 3-2-isfrom round through relay 29. to normally open the circuit closer-including theconta-ct 25, and then to ground leaving the relay normally deenerg-ized. In the :operationof the; device, when the switch I8 is' on the-contacts .32" :andt33 commonuthera to and the film B breaks permitting circui-tcloser toclosethe-circuit :through the secondary of A the transformer-.32 andirelay-winding to ground, the relay z=29i is energized-.. and draws :the switches .28 and 30+ to closingpositions Thisacom-pletes a lockingcircuit-for the relay 29 to ground-through the-tcircu-it closer andobviates possible sparking of the closer-on the "breaking of the circuit-theretoa lhe engagement-oi-the switch 28 with its front; contact completes Jtheicircu-it to the supply line ithroughq-the switch .I 8 and-the solenoid-2 2; which energizes; the latter; causing-t the arma ture for core 23 I thereofeto move the arm 2 0 about itspivot 2 I. to have theshutter- I 9 close the: open ing I4, andat th-e-sameitime moving the: switches 34-011 andthack: from the. iclos-ing-tpositions. I- The movement of the :switch34- for; the contacts? opens the circuitithrough,the relay 2 9-'and-cuts the-power" supply ofiifrom the solenoid 221 The movement i of the switch 34- for the contact 33 opens the circuit to the motor I5 andrenders it inoperative, since thepower circuitimaymb'e traced through the switch .I 8 andlthe. switch 34 oncontact3'3 to'such motor.

Theldeenergization of; the solenoid-f 22 "will not return its armature or core 23, .and" in turn the switches 34 for the contacts 332 and'3'3Q-andthe arm 23"oi the shutter-22 tov their originalposition, since the usual biasing spring has been eliminated. When the switch I8 is manually operated to engage the contact 38 the operation is the same, except the system will not render the motor It: inoperative when the film B breaks, as the switchmsa has been by-passed by this action;

The elimination of sparking at the circuit closer through the use of the relay 29, switch arm 30 and the locking circuit reduces possibility of fire hazardsthrougli ignition of the film B resulting from such-sparks that would otherwise occur at the circuit closer having the contact 25.

Theclosi-ngof the shutter I9 shuts ofi light from the opening M on the breaking of the film B, and thereby avoids setting fire to the latter, as the said film will be separated from the action of the light in'theprojector machine.

What is claimed is:

1. Operating mean-s for a dowser of a motion picture. machine including a solenoid for/moving-the dowser to an ioperativeposition an elece trio circuit .forsaid.- solenoid, a springactuated switch insaidcircuit normall-yheldin open posi tion by the motion picture film and a double pole relayswitch between saidspringswitchand saidsolenoidiadapted to close thecircuit to said solenoid andgroundthe circuit to saidispring switch upon clo-sing of. the/latter.

2. Operatingmeansfor. a dowserlof aim'otion picture projecting machine including a solenoid for Imoving-said dowser to an operative position, an electric circuit for said'solen'oid; aspring actuated switch in saidci'rcuit normally held -in'an open position by-the motion picture film, a double pole relay. switch interposed in said circuit between saidmspringa-switch and said solenoid operable uponclosingof said spring. switch i to close thecircuit'. to saidisoleno'id and ground'ithe 'circuitto said spring switch,.and a switch actuated loylsaid. Lso-lenoidl for; opening.v said circuit upon energizing of saidfsolenoid'.

JOSEPH 'D'. EDIVIONDSONI REFERENCES CITED Theafollowing; references are of record in the file of l this-patent-z- UNITED STATES" PAT ENTS l Number- Name Date 1,-000;1-54? Crosier l s e Augz:8, 1-911 1,142,103 Klink c sJune-8 1915 1,'261;029- Hulseyfet ali Apr. 2; 1918 1,658,594 Feeney et a1. Feb-.17; 1928 1,725,574.. Feeney et al. Aug. 20,-.1929 1,7995'1'541'H" Brook 1. Apr-53 1931 1,804,340 Hoffmarriet a1. e May 5-, 1931 1 ,946,875. Nichol-son Feb; 13,-=1-934= FOREIGN 1 PATEN'I'S 5 Number. Country Date-..

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